This Critically Endangered bush frog is known only from the type locality “Kottigehar, Kadur”, and from a recently discovered population at Bhadrea, in Chicamangalore District, Karnataka, in the Western Ghats of India. Its distribution is severely fragmented and its habitat is declining in both quality and extent. Cash crops such as coconut and cashew are the main culprit for this habitat loss. Urgent action needs to be taken to determine the current population size and distribution of the species as well as investigating the possibility of implementing an ex situ captive breeding programme.

Urgent Conservation Actions

Determine the current population status of the species and the limits of its distribution range; investigate the feasibility of a captive breeding programme.

The Kottigehar bush frog was originally described as a new species by C.R.N. Rao in 1937. It was initially placed with the bubble nest frogs (genus: Philautus) in the Afro-Asian tree frogs (Rhacophridae) and assigned the scientific name Philautus kottigeharensis based on a single specimen from Kottigehar. It was transferred by Bossuyt and Dubois from Philautus to the tropical frogs in 2001. Very little is known about this species.

Evolutionary Distinctiveness

Order: Anura

Family: Micrixalidae

The Kottigehar bush frog, along with its ten other close relatives in the genus Micrixalus, has previously been placed in the family Ranidae (the “true frogs”) under the genus Rana (also referred to as the “true frogs”). The true frogs have the widest range of any family among the frogs and toads, found in nearly all regions of the world except Antarctica and most common in Africa and southeastern Asia. This family was formerly the largest within the frogs and toads, containing well over 600 species. It has recently been split into several different families, one of these being the Micrixalidae (or the “tropical frogs”).

The tropical frogs are a family within the sub order Neobatrachia or the “modern frogs and toads”, which contains the more recently evolved groups. They diverged from all other species of amphibian about 70 million years ago – five million years before the extinction of the dinosaurs. The family comprises only eleven species that are small and slightly warty in appearance, with large adhesive discs on the tips of their fingers and toes. They are adapted for life in forest streams, using their powerful legs and webbed feet to negotiate currents.

Description

This bush frog is a relatively small species, reaching lengths of just 23 mm. It is deep bronze in colour along its back and the sides of the head, body and limbs are barred by darker stripes. Well-developed, adhesive discs are present on the tips of the fingers and toes, which are dark in colour on both surfaces. The toes are webbed, but the fingers are free of webbing. The webbing between the toes is dark, with the toes being characteristically deep black in colour. The throat is bronze to match the back, and the stomach is either dark in colour or sometimes bright orange. The undersurface of the thighs is red and the sides of the body (beneath the dark stripes) is either yellowish or white. The back is covered in small warts with lateral folds of skin, whilst the skin of the throat, stomach and thighs is smooth. The hind limbs are long and muscular.

Ecology

Like other members of the genus Micrixalus, the Kottigehar bush frog probably has aquatic larvae in streams within its range. Although little is known about this species, it is thought to be similar in behaviour to two other groups of closely related stream-dwelling frog: the cascade frogs (Amolops sp. of the family Ranidae) and the splash frogs (Staurois sp. also of the family Ranidae). Many frogs and toads live along side flowing water because it provides a constantly high level of humidity that helps maintain their moist skin, through which much of the gas-exchange for their respiration occurs. Additionally, streams provide a convenient means of escape from certain predators. The adaptations to stream life are visible in the morphology (or physical form) of the frog. The adhesive discs on the fingers and toes help them to climb the wet rocks around streams when traversing stream banks or exiting the water. In addition, their webbed feet and powerful hind legs enable them to be strong swimmers.

Although more research is required to collected detailed life history information about this species, it probably feeds on small invertebrates, both aquatic and otherwise. The tadpoles of the Kottigehar bush frog may, like those of the cascade frogs, possess enlarged mouths adapted for sucking onto rocks both for feeding and to prevent them from becoming washed away. They may also have powerful tails for swimming against strong currents.

Habitat

The Kottigehar bush frog is thought to be a forest species, living around and breeding in streams at fairly high altitudes in the mountains of India’s Western Ghats. It has recently been collected close to a road and a stream.

Distribution

Known only from the area where it was originally collected in the locality of "Kottigehar, Kadur", and from a recently discovered population at Bhadrea, in Chicamangalore District, Karnataka, in the Western Ghats of India, at an altitude of approximately 1,000 metres above sea level. It appears to have a very small distribution.

Considered to be in decline by the IUCN Red List of Threatened Species.

Status

Listed as Critically Endangered on the IUCN Red List of Threatened Species because its area of occupancy is probably less than 100 km sq., its distribution is severely fragmented, and there is continuing decline in the extent and quality of its habitat.

Threats

The major threat to the species is general habitat loss as a result of deforestation for agriculture, including paddy fields and cash crops such as coconut and cashew.

Conservation Underway

It is not known whether this species occurs in any protected areas, but it is protected by national legislation.

Conservation Proposed

Further survey work is urgently required to determine the current population status of the species and the limits of its distribution range. It is also important to find out more about the life history of this species to better understand how to preserve its habitat requirements.

Habitat conservation is a priority within the restricted range of this species, which should ideally include a community conservation programme gathering support from local people who carry out coconut and cashew farming on this land. This may engender new methods of sustainable land management in this area, allowing for current land uses and the conservation of some important habitat for the Kottigehar bush frog.

In addition to conserving native habitat for this species, the IUCN Technical Guidelines for the Management of Ex situ Populations, part of the IUCN Red List of Threatened Species, recommend that all Critically Endangered species should have an ex situ population managed to guard against the extinction of the species. An ex situ population is ideally a breeding colony of a species maintained outside of its natural habitat, giving rise to individuals from that species that are sheltered from problems associated with their situation in the wild. This can be located within the species’ range or in a foreign country that has the facilities to support a captive breeding programme for that species. Since the Kottigehar bush frog is categorised as Critically Endangered, the possibility of a captive breeding programme for this species should be investigated.